I get "Syntax error in UPDATE statement" in vb.net Visual Studio 2010

I am developing an information system that works with a connected data source / MS Access database. The question is kinda cliche but I can't seem to find a proper solution from the similar ones I have come across.

I hope that I can get a solution that works without overly formatting the code. I would also like to get solutions to my code grammer / syntax that could possibly cause some other problems in the above code

Password is a reserved keyword in ms-access. You need square brackets around it, but then you have another problem. You should set the parameters BEFORE executing the query, and albeit OleDb doesn't recognize parameters by name but by position, giving a matching name with your placeholders doesn't hurt

Dim updateCmd As OleDbCommand = New OleDbCommand("UPDATE Users
SET [Password] = @ConfPasscode
WHERE [Usernames] = @UsersID", myConnection)
With updateCmd.Parameters
' First ConfPasscode because is the first placeholder in the query
updateCmd.Parameters.AddWithValue("@ConfPasscode ", txtConfirmPasscode.Text)
' Now UsersID as second parameter following the placeholder sequence
updateCmd.Parameters.AddWithValue("@UsersID", txtUserID.Text)
End With
Dim rowUpdated = updateCmd.ExecuteNonQuery
....

In response to the comment below of Andrew Morton, I should mention to the problems caused by AddWithValue. In this context, with just strings, it is a performance problem, in other context (dates and decimals) could escalate to a correctness problem.

Also, as noted in another answer, the correct method to use for an Update query is ExecuteNonQuery, but also ExecuteReader can update your table but because it build an infrastructure required only when you have something to read is less efficient for an Update. In any case just use only ExecuteNonQuery or ExecuteReader